Early thoughts on the Conklin Mark Twain crescent filler fountain pen.

This pen was part of my haul from the London Pen Show in March 2023. I do already have a pair of these, also bought at a pen show several years ago, one in red and one in a dark orange, (which might be called coral) but was newly tempted by this handsome black chase edition with rose gold colour trim and a stealthy black-coated nib.

Conklin Mark Twain crescent filler, black chase and rose gold colour trim.

The pen is based upon the original, designed by Roy Conklin between around 1897-1901 and featuring a quick and easy filling system. Advertisements at the time claimed that the pen “fills itself in four seconds.” Whereas the original was made of ebonite, the modern one is of some sort of plastic or resin, but has a pleasing, glossy finish and an attractive wave pattern on the barrel and cap for decoration and texture, like the original.

The cap features a sprung metal clip: you press the top end inwards to raise the clip, making it easy to slip the pen into a pocket one-handed. There is a broad metal cap band, with Conklin on the front and a facsimile of Mark Twain’s signature on the back.

The cap unscrews, in about one and half turns. The nib is a size 6 steel one, with a distinctive crescent shaped breather hole and an imprint of the Conklin logo and Toledo, USA. Mine has an M for medium.

Stealthy black nib. Not-so-stealthy rose gold trim.

The nib and feed housing can be unscrewed from the section, for ease of cleaning. I found the nib on one of my older pens to be rather rough but it was interchangeable with one from a Jinhao X450. Separate replacement nib units from Conklin are also available (for example from Cult Pens at £28.00).

On this new black pen, the nib has a glossy black coating. Mine is a gusher. Whereas I do generally like a wetter nib for lefty overwriting, this one was leaving such a volume of ink on the paper that I needed to try to narrow the tine gap slightly by gently bending the tip downwards. This has helped and I may yet try using a drier ink, such as Pelikan 4001 Konigsblau at my next fill.

There is a single rose-gold coloured ring separating the section from the barrel. However the barrel does not unscrew, or at least I do not think it is meant to, and I have not tried to force it. It is not necessary to remove the barrel to fill the pen.

Beneath the barrel, there is a large ink sac, or reservoir. To fill the pen, you simply twist the locking ring to align a gap in the ring with the crescent-shaped filler button. Dip the nib in your ink bottle. You can then press this button causing a long flat metal bar inside the barrel to deflate the reservoir, creating a vacuum which then draws up ink as the sac regains its shape. After a few presses, when you cease to hear bubbles, you have a good fill. Twist the locking ring back again, to prevent unintended ink ejection and you are all set. The pen holds a mass of ink.

Mark Twain (1835 – 1910) was an early fan of the Conklin’s crescent filler pen, for its ease of filling and also for the added benefit of it not rolling off a table.

This won’t roll anywhere.

Size and weight.

When capped, the pen measures about 140mm. Uncapped it is around 129mm. The cap can be posted, but it then becomes very long at around 166mm and the pen is plenty long enough without posting. It weighs about 30g, comprised as to 19g for the pen and 11g for the cap. I find the size and weight to be very comfortable. The only issue in terms of comfort is to ensure that the crescent filler button is roughly in line with the nib and not facing too far one way or the other so as to be in your way as you hold the pen.

Some do’s and don’ts.

On my coral-coloured pen, I found that the barrel was not securely glued to the section and I was able to remove it. The rubber sac stays attached to the section. There are metal threads inside the barrel. If you do remove it, you can then remove the crescent filler. However you should apply some talcum powder to the sac before reassembling. I later re-visited this pen to find that the barrel was stuck and would not unscrew. When I forced it, I found that the sac had become stuck to the inside of the barrel and that by unscrewing the barrel, I had torn it from the section. I have still got the bits.

My Conklin crescent filler family.

Another thing to avoid is immersing the pen in water. If flushing the pen, be careful to keep the crescent filler clear of the water as you do not want water getting in the barrel through the openings.

One handy tip when capping the pen, given that the cap threads have four entry points, is to work out how best to align the cap clip with the crescent filler button. To do this, insert the pen loosely into the cap, with the nib in line with the pocket clip. Then turn the pen left (anti-clockwise), and listen for the clicks. You can then find by trial and error whether you need 1, 2, 3 or 4 clicks to the left, before turning the pen the other way to screw the cap on. Once learned you have perfect alignment every time.


I was fortunate to find this pen greatly discounted at a pen show. A more usual price would be closer to £200.00 and I do think that at full price a well-tuned nib is in order. If not in gold, then at least a really delightful steel nib (such as one finds on a Diplomat, Onoto or Otto Hutt, for example) would be appreciated. As it is, all three nibs on my crescent filler pens needed some attention.

However, I love the filling system which is very convenient and satisfying. Also I find the girth, length and weight of the pen to be ideal. Having owned this pen for a month now, I can report that it has not suffered from hard starts and has performed well. And so with that one caveat that a nib might need a little fine-tuning, I think the pen is good to have, as a modern reminder of an important piece of history in fountain pen development.

Cap and crescent filler alignment achieved.

Happy Fountain Pen Day

In recognition of today being Fountain Pen Day, I thought to do a short post about one of the pens that I have with me today.

This is the Conklin Mark Twain Crescent Filler, red chase. This was one of my happy purchases from the London Pen Show last month.

I had long been interested in the Crescent Filler and enjoyed reading of its associations with Mark Twain. The current model is not quite the same as the one from the original Conklin pen company that he would have used. I did spot a vintage black Conklin crescent filler at the same pen show and noticed how much thinner it was than the modern one.

At a very attractive show price, I came away with two of these, one in orange (or coral chase) and one red chase.

Conklin Mark Twain Crescent Fillers, in coral chase and red chase finish.

The beauty of these pens is the lovely nostalgic feel of dipping into a bottle of ink, squeezing the crescent-shaped filler button slowly a few times and allowing the sack to fill, before locking the button again by twisting the collar back again.

The only downside is that you cannot see how much ink the pen has. There is no ink window. Also the barrel is glued to the section and so you cannot unscrew it to gauge the ink remaining. (Actually, on one of my models, the glue seal had been broken and so I was able to open it, but even then you cannot see through the dark rubber material of the ink bladder).

One thing to remember when washing these pens, is to avoid allowing water in to the barrel, through the slot where the crescent filler sits. This is because the bladder has a dusting of talcum powder to stop it sticking or rubbing on the filler bar.

If you do unscrew the barrel, then the metal filler bar can be removed. I was impressed at how long a bar there is, to press on the ink bladder and so this helps to get a good fill. To put it back again, with the crescent pushing out through the slot, you will need some tweezers. A Swiss army knife came in useful here.

Quite how much ink it draws up, I have not yet measured. However, I did find that, with a medium nib, I wrote 37 pages of an A5 size journal on the first fill, which I was very happy with. That was the coral chase model, with Diamine Oxblood ink.

My red chase Crescent Filler, prior to nib swap with a Jinhao X450.

On the red model, this came with a Conklin Fine stainless steel nib. This turned out to be slightly catchy. On close inspection, it seems that the left tine was fractionally longer than the right so that in normal writing, on side strokes from left to right, the proud edge was snagging on the paper. I need to have a go at it with my handy micro-mesh kit, also bought at the same show.

Meanwhile however, I was delighted to read that the nibs of the crescent filler are easily swapped. The nib, feed and housing can simply be unscrewed from the section. Alternatively you can extract the nib and feed, which are friction fit, by pulling them out carefully, taking care to avoid damaging the fins of the feed, or distorting the nib itself.

Yesterday evening I swapped the nib with one from a Jinhao x450. I have not swapped the feeds, but just the nibs.

I now have the red crescent filler, with a lovely Chinese Jinhao x450 medium nib and filled with Aurora Blue-Black ink (same pen show as well), which I am enjoying.

Coincidentally, I had to visit the China Visa Application Service Centre in London today, to pick up my visa for a trip to China later this month, so it was good to have my red crescent Jinhao-nibbed Conklin for company.

My haul from the London Pen Show 2017.

This was my fourth time, attending the annual London Writing Equipment Show (LWES).  It was held on 1 October 2017, at the Holiday Inn, Coram Street, near Russell Square. Knowing broadly what to expect, I had been much looking forward to it.

Oh my, what a treat for the fountain pen obsessed  enthusiast! The venue comprises one large main function room at the hotel, plus the adjacent corridors, all filled with lines of tables, covered with enticing displays of fountain pens old and new, inks, spare parts, accessories and other paraphernalia. There is something for everyone, whatever your level of interest in this addictive hobby.

This year, for me there was an added bonus, of finding several familiar new friends from the recent Pelikan Hub, just over a week earlier. It was good to see them again and to have a chat and share the excitement.

It was very warm inside and rather too crowded, until it thinned out in the afternoon. It is a good idea to find a coat rack and leave your jacket somewhere. I had brought along some cash but not quite a big enough bag, as it turned out, for the purchases I made. I had not come with any firm ideas of what to look at. Last year I bought a vintage Parker 51 from Graham Jasper’s table. I had a vague plan to pick up another, but did not in the end. I had also planned to have another look at the Conid Bulkfillers, the Belgian made, precision-engineered masterpieces that I eye up every year, although I still came short of buying one.

Thus browsing, with an eager eye and an open mind, I managed to limit myself to just five new pens, (all new, but all stainless steel nibbed, modestly priced pieces), three bottles of ink and a craft box of assorted grades of micro-mesh for those occasional attempts at nib adjustments.

My day’s shopping: Kaweco Allrounder, Conklin Mark Twain crescent fillers in red and coral, TWSBI Classic and a mystery pen. Plus three bottles of ink and a micro-mesh kit.

My first catch was the Conklin Mark Twain Crescent Filler. I had been attracted to these from seeing them online, but thought them to be rather over-priced for a stainless steel nib pen. However, at a very attractive price at the Show, I picked up both a Red Chase and a Coral Chase model, with fine and medium nibs, respectively.


Next, and still before reaching the main hall, I lingered at the Kawecos. I have been using a Kaweco Dia 2 in recent months, which I have been delighted with and find super comfortable. At the Show, I saw the Kaweco Student and the Kaweco Allrounder, for the first time in the flesh. I was drawn to the Allrounder in a vibrant red aluminium (I think) body. It takes the same nib and feed unit as the Dia 2 or Al-Sport. I bought the pen with an Extra Fine nib, plus a Fine as a spare. These nib units are only about £8.00 and can often be fantastic, if well made.

Kaweco Allrounder, with Extra Fine nib.

Next I bought a spare bottle of ink, the Conway Stewart Tavy, by Diamine. I bought a bottle of this two shows ago and have used it a lot, as an attractive blue black. It is sometimes out of stock on web-sites and so I was pleased to get a spare.

A few tables on, I met the gentleman selling Aurora pens and inks, who remembered me from previous years. It was wonderful to see these stunning beauties on display, including the Optima in what I presume was the burgundy auroloide resin, a grail pen for the wish list although surprisingly light to pick up. However I did buy a bottle of Aurora Blue Black ink, only available since April which I had been keen to try.

I had a look at the Onoto pens. Again, very desirable, but quite an expensive outlay for an unplanned purchase.

Now – the main hall! It can be a bit overwhelming, the sight of so many pens and people all in one place. A prominent display of Pelikans with a giant plastic Souveran model, indicates Niche Pens’ table, with a good range of Pelikan pens to handle, including the M120 and the entry level Pelikano.  Next there were Noodlers and TWSBIs. At the vast vintage Parker table, (Graham Jasper) I was impressed to see an open, 80-pen case display of Parker Duofolds, grouped with about six of each colour. Another grail pen.

Several tables had nostalgic fountain pen branded signage of a bygone era and I regret not taking some photos of these lovely displays.

Another pen purchase, was an unbranded, large clear demonstrator pen with a black cap, displayed in gift box with a syringe included for eye-dropper filling, as an alternative option to the included converter. There were several colours and I chose one with nice blue end-cap, section and strikingly bullet-shaped barrel end. The nib looked to be a very smart, stainless steel Medium with some scroll work but with an empty space where you might normally expect to see the words Iridium Point, Germany. This I call my mystery pen. I also found a stack of Micro-mesh craft kits and added that to my stash, thinking it would be useful to have the means to do some very rudimentary nib-smoothing if the need arose.

A mystery pen. No noticeable branding on nib, pen or packaging. But it is a beauty!

Several fascinating laps later, I was nearly ready to go but paused again at the TWSBI’s. It was at this same show in 2014 that I bought my first TWSBI, a clear Vac 700 that I love and use regularly at work.  I have since added a Diamond 580 and an Eco. Now, someone next to me was trying the TWSBI Classic in a cute Robin egg blue. I had not handled one before and rather liked the faceted cap and barrel, the shiny metal piston knob and the small clear ink window (picture your favourite ink here!). I bought one, in white. Not exactly an Aurora but it has an ink window. They also had a few KWZ inks for sale (of which I have read great reviews) and I bought a 60ml bottle of Azure #4.

Oh, go on then. A TWSBI Classic, new model with postable cap. Now inked with Sailor kiwa-guro.

Having a New Pen Day x 5 was rather indulgent, admittedly. I therefore decided to ink only one more pen a day, throughout the week, to prolong the enjoyment. And it has been enjoyable. Each one has been a success and I am thrilled with my purchases.

Conklin Mark Twain Crescent Filler. Currently inked with Diamine Oxblood and going nicely.